Tags:

If you see the “Disk contains BIOS metadata, but is not part of any recognized BIOS RAID sets. Ignoring disk sda” error message during OS installation, then you need to remove the raid metadata the “classic” way:

Tags:

If you are trying to send emails from a local application on a CentOS machine that is not a primary mail server, then you might hit the
Sender address rejected: Domain not found (in reply to RCPT TO command)) error. In this case you need to rewrite the outgoing address that is being rejected to something that make sense with the proper domain for the users.

Intrusions can take place from both authorized (insiders) and unauthorized (outsiders) users. My personal experience shows that unhappy user can damage the system, especially when they have a shell access. Some users are little smart and removes history file (such as ~/.bash_history) but you can monitor all user executed commands.It is recommended that you log user activity using process accounting. Process accounting allows you to view every command executed by a user including CPU and memory time.